Flexible coupling



A118- 16, 1949- v. '1. BOT-rms 2,479,058

FLEXIBLE COUPLING Filed Sept. 25, 1944 y f v HTTONEK me A. 1s, me 2,419,058

UNITED STATES PATET clsicaA Apppolirzltnoseptmber 25, 1944, Serial No. 555,67.

4Clalml. ((71.285-90) all types of tubing and pipe.

Light weight'metal tubing is frequently used to conduct various fluids and gases at high pressures and under conditions where the tubing is subjected to continuous vibrations and compressional, tensional and nexing stresses or under conditions whereit may have to withstand impacts or shocks. Examples are tubingl installa- Anotherl object of my invention is to provide tions in airplanes, ships, and railroad locomoa flexible coupling for plain end tubing that will tives and cars. To withstandv this abuse the withstand considerable vibration and end pull. lengths of tubing in the line are joined by cou- Still another object of my invention is to proplings which permit at least a limited universal vide a flexible coupling that is simple in construcmovement. However, to have practical utility l5 tion and inexpensive in operation. the coupling must be iluid tight at relatively high Other objects and advantages of my invention pressures under the conditions described above will be apparent during the course of the followand must be of relatively simple and inexpensive ing description. construction. In the drawing forming a part of this specifica- Heretofoe, various types of flexible couplings tion and wherein like numerals are employed to have been devised but none of these have proven designate like parts hIOlIghOut the Same, to be entirely satisfactory. vMany of these cou- Fig. 1 is an elevational view showing a flexible plings require mechanical preparation of the coupling embodying my invention, tube ends such as flaring, beading, grooving or Fig. 2 is a longitudinal sectional View taken on the swaging on of a ferrule. These operations the line 2--2 of Fig. 1, are diillcult, tedious and time consuming. Fur- Fig. 3 is a transverse sectional view taken on thermore, where relatively short sections of tubthe line 3-.1 of Fig. 2. and y ing are used or Where the line is relatively long Fig- 4 iS an exploded perspective view showing the cost of preparing the tube ends is prohibitive. the relation between the gripping elements. Other couplings have been used which connect gasket and tubing. plain end tubes. The latter couplings commonly In the drawing wherein for the purpose of ilinclude either a rubber gasket or a metal ring lustration is shown a preferred embodiment of to seal the joint between the coupling and the my invention the numeral I0 designates a contube ends. However, a coupling employing a rubventional nipple. The end Illaof the nipple is ber gasket will not withstand tensional stresses screwed into a pipe II. The numeral I2 desigor end pull, since the only hold on the tubing is mitesa section of plain end tubing which exthe frictional engagement of the rubber gasket; tends a short distance into the central passage and a coupling employing a metal sealing ring Illb of the nipple. As Shown in Fig. 2, the tubwill not withstand vibration. ing I2y nts loosely within the passage. To seal This invention is an improvement on the presthe joint between the nipple Il) and tubing I2 I ent types of plain end couplings. I provide gripping elements between the gasket and the tubing and a compression nut that can be tightened to sui'iiciently compress or squeeze the gasket so that the gripping .elements bite into the tube sections. This eliminates preparation of the tube ends and provides a construction that will withstand considerable end pull and which will not be weakened or loosened by vibration. When the tubing, compression nutI gasket and gripping elements are combined and correlated in this manner the gripping elements have 'a positive gripping action on the tubing to resist endv pull while the gasket holds the gripping elements securely in place and a resilient backing which to new and useful im-` 2 allows slight motion without loosening. It has a further advantage in that the connection between the gripping elements and the tubing need not form a seal since the gasket contacts the tubing with sumcient force and over a suficient area to provide an eiiicient high pressure seal.

An important object of my invention is to provide a exible coupling that does not require mechanical preparation of the tube sections.

provide a gasket I3. The gasket surrounds tubing i2 and is conned at one end of the nipple I 0 by a compression nut I4. The end Ila of the compression nut threadedly receives the end Ic of the nipple and the end Mb thereof is formed with a central opening I 4c through which the tubing passes. When the compression nut I 4 is tightened on the nipple the rubber gasket I3 is compressed or squeezed around the tubing. 'I'he gasket may be of natural or synthetic 'rubber or any other suitable material that can be deformed and which has the necessary resiliency. The gasket I3 provides a uid tight seal between the nipple and the tubing but the compressional forces set up in the gasket do not create suiilcient amiaosa friction between the gasket and the tubing to overcome any substantial end pull on the tubing. I have found, however, that if gripping elements Il are inserted between the' gasket and the tub-4 ing of compressionai forces created in the gasket by compression nut I 4 are sumcient to causeV the elements to bite into the tubing. In actual practice the gripping elements i5 do not bite deeply into the tubing but merely score its outer surface. However, even a relatively light scoring of the tubing provides substantial resistance to end pull. As best shown in Figs. 2 and 4, Vthe gripping elements are preferably in the form of threaded studs. They may be molded into the gasket when `it is formed or subsequently either threaded therein or placed in suitable recesses in its inner periphery. While I have shown the stripping elements in the form of threaded studs, it is to be understood that they may assume other shapes. The precise shape of t e gripping elements is not important. It is sumcient that they contactthe tubing and that the contacting surface be suiiiciently rough or provided with teeth or serrations that will bite into the tubing. It is desirable that the gripping elements be transverse or substantially transverse to the tubing axis in order that they offer maximum resistance to end pull.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope'of the appended claims.

Having thus described my invention, I claim:

1. A iiexible coupling for tubing comprising an externally threaded member, a compression nut threaded on said member having an opening, tubing extending into the nut through said opening, a gasket of resilient material confined within the nut and against one end of the externally threaded member, said gasket surrounding the tubing and compressed into frictional engagement therewith by the compression nut, and

spaced apart tube gripping elements disposed` circumferentially about the periphery of the tubing beneath and covered by the resilient gasket .and lying between the gasket and the tubing said gripping elements urged forcibly against the tubing by compression of the gasket whereby said elements supplement the frictional retention of the tubing by the gasket with a positive holding action.

2. A fiexible coupling for tubing comprising an externally threaded member, a compression nut threaded on said member having an opening, tubing extending into the nut through said opening, a gasket of resilientmaterial confined within the nut and against one end of the externally threaded member, said gasket surrounding the tubing and compressed into-i'rictional engagement therewith by the compression nut, a tube gripping element embedded within and covered by the resilient gasket and having teeth or seri-ations against the tubing whereby compressive forces imposed upon the gasket by the compression nut and externally threaded member cause, said teeth to bite into the tubing and providing a positive holding action.

3. A flexible coupling for tubing comprising an externally threaded member, a compression nut threaded on said member having an opening, tubing extending into the nut through said opening, a gasket of resilient material conned within the nut and against one end of the externally threaded member, said gasket surrounding the tubing and compressed into frictional engagement therewith by the compression nut, spaced apart Iexternally threaded gripping elements beneath `and covered by the resilient gasket and lying between the gasket and tubing, said elements disposed circumferentially about the periphery of the tubing and forced against the tubing by compressive forces imposed upon the. I

gasket whereby the threads bite into the tubing.l 4. A tube gripping and sealing assembly for use in fiexible couplings and tube fittings with plain end tubes i comprising a ring of resilient A material, separate gripping elements spaced apart circumferentially about the inner periphery of the ring and covered by the resilient material of the ring, the inner diameter of the assembly being at least that of the tube upon which it is to be applied.

VINCENT T. BO'ITING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,030,237 Hall June 18, 1912 1,823,061 Pearson Sept. 15, 1931 2,035,925 Seamark Mar. 31, 1936 2,212,745 McIntosh Aug. 27, 1940 2,232,513 Confer Feb. 18, 1941 2,283,975 Dillon May 26, 1942 

